Methods and systems for frequency reuse in multi-cell deployment model of a wireless backhaul network

ABSTRACT

Systems and methods for frequency reuse in a multi-cell deployment model of a wireless backhaul network are shown. According to embodiments, a wireless backhaul network includes a plurality of cells, each of which includes one or more hubs supporting wireless backhaul communication utilizing a cell deployment geometry and wireless communication frequency assignments adapted to facilitate heterogeneous cell configurations within the wireless backhaul network. In particular, embodiments provide frequency planning for initial deployment, build out, and expansion of a plurality of cells providing wireless backhaul communication so as to implement a predetermined wireless frequency reuse pattern providing alternating utilization of a plurality of wireless communication frequencies by the cells of the backhaul network.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of co-pending,commonly assigned, patent application Ser. No. 12/950,006 entitled“METHOD AND SYSTEM FOR FREQUENCY REUSE IN MULTI-CELL DEPLOYMENT MODEL OFA WIRELESS BACKHAUL NETWORK,” filed Nov. 19, 2010, the disclosure ofwhich is hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to implementation of a communicationnetwork, and more specifically to frequency reuse in wireless backhaulnetworks.

BACKGROUND OF THE INVENTION

Communication between nodes in a communication network requires theconnection of end customers to their respective telecommunicationproviders. In that manner, end customers are able to communicate witheach other no matter which provider is used by a respective customer.Communication between customers is implemented through atelecommunications infrastructure (e.g., wireless core network forpacket and circuit switch voice or data) supporting each of theproviders. A typical problem facing telecommunication providers isconnecting the end customer to the telecommunications infrastructure.

A backhaul network connects remote nodes back to their respective hubsto effect communication between the remote nodes and respectivetelecommunication providers. Remote nodes facilitate communication withend customers (e.g., mobile units, fixed units, etc.), such as withinsmall cells (e.g., picocells). For greater scalability and a moreeconomical solution, this connection can be configured over a wirelessconnection, as opposed to a more typical wired connection. For instance,as the number of users, or as demand for bandwidth grows, throughout ageographic area, more hubs and remote nodes can be added to service theincrease in demand. As a result, a particular geographic area may besupported by multiple hubs, each of which supports multiple remotes.

However, as the network of hubs and remotes grow within a geographicarea (e.g., through the addition of hubs and remotes to a region tosupport traffic growth), wireless communication between the hubs andremote nodes may experience problems atypical of a wired backhaulnetwork. For instance, communication between remotes and hubs mayinterfere with each other, thereby, in part, reducing overall datathroughput rates, increasing outage areas within the geographicfootprint of the network, and increasing non-uniformity of signalcoverage and throughput throughout a geographic area. Accordingly,although the densification of the network will allow more traffic to besupported, such densification can increase self interference within thebackhaul network unless there is proper planning.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to systems and methods for frequency reusein a multi-cell deployment model of a wireless backhaul network.According to embodiments of the invention, a wireless backhaul networkincludes a plurality of cells, each of which includes one or more hubssupporting wireless backhaul communication utilizing a cell deploymentgeometry and wireless communication frequency assignments adapted tofacilitate heterogeneous cell configurations within the wirelessbackhaul network. In particular, embodiments provide frequency planningfor initial deployment, build out, and expansion of a plurality of cellsproviding wireless backhaul communication so as to implement apredetermined wireless frequency reuse pattern providing alternatingutilization of a plurality of wireless communication frequencies by thecells of the backhaul network.

Frequency reuse patterns provided according to embodiments are adaptedto accommodate heterogeneous deployment and expansion in the wirelessbackhaul network by dividing each cell of a selected cluster of cells toprovide added sectors. Frequency assignments are made according toembodiments such that adjacent cells provide orthogonal frequency faceswith respect to one another. The term “orthogonal frequency face” asused herein means a cell edge of a cell associated with a frequency ofthe plurality of wireless communication frequencies which is adjacent toa cell edge of another cell associated with a different frequency of theplurality of wireless communication frequencies to thereby mitigatemutual interference. The frequency assignments are further madeaccording to embodiments such that, where orthogonal frequency faces arenot maintained between adjacent cell edges as sectors are added,non-broadside common frequency views are provided with respect to theparticular opposing sectors for which orthogonal frequency faces are notprovided. Such non-broadside common frequency views comprise theazimuthal direction of the opposing sectors being offset, such as by 20°or more, to thereby mitigate mutual interference. Accordingly, theforegoing frequency reuse patterns are adapted to accommodateheterogeneous expansion in the wireless backhaul network by dividingeach cell of a selected cluster of cells to provide added sectors whilemitigating interference by maintaining the orthogonal frequency facerelationships and/or providing non-broadside common frequency viewsbetween opposing sectors in the wireless backhaul network.

Using such network expansion frequency reuse adaptation techniques,cells of a wireless backhaul network may be initially deployed in alower capacity configuration and selected portions of the wirelessbackhaul network expanded (e.g., to provide increased capacity and/ormore frequency robust configuration) as need or desire dictates. Forexample, a cluster of cells (e.g., cells serving an area of increasedcommunication traffic, with additional subscriber deployments, etc.)previously deployed as omni-directional cells each utilizing a singlewireless communication frequency within their respective cell servicearea may each be divided into a plurality of geographic sectors (e.g.,two, four, etc.) to thereby utilize a plurality of wirelesscommunication frequencies within their respective cell service areas.Similarly, a cluster of cells previously deployed as multi-sectoredcells (e.g., two sectors, four sectors, etc) each utilizing a pluralityof wireless communication frequencies within their respective cellservice area may each be divided into still more geographic sectors(e.g., four sectors, eight sectors, etc.). The orthogonal frequency facerelationship between each cluster cell and corresponding cell externalto the cluster is maintained as the cells of the cluster are expandedusing the network expansion frequency reuse adaptation techniques inaccordance with embodiments of the invention.

Frequency reuse patterns utilized according to embodiments of theinvention for providing network expansion frequency reuse adaptationtechniques may be used in various combinations, such as to provideincreased capacity and/or frequency robust configurations. For example,a second frequency reuse pattern herein may be overlaid, or partiallyoverlaid, over a first frequency reuse pattern for assigning additionalwireless communication frequencies to hubs in a manner adapted toaccommodate expansion in the wireless backhaul network.

Embodiments of the invention preferably implement frequency reusepatterns which are adapted to provide the aforementioned orthogonalfrequency faces with respect to cells of the network. For example, afrequency reuse pattern including cell frequency assignment layoutswhich differ from cell to cell within the wireless backhaul network,although providing alternating utilization of a plurality of wirelesscommunication frequencies by the cells, may be used according toembodiments of the invention. In one embodiment of the presentinvention, a backhaul network includes a plurality of cells, each ofwhich includes one or more hubs supporting wireless backhaulcommunication over four geographic sectors. A first tier of theplurality of cells includes a center cell configured to support a firstalternating frequency reuse pattern of a first channel and a secondchannel over four corresponding geographic sectors. A second tier of theplurality of cells surrounds the first tier. The second tier includes afirst cell configured to support the first alternating reuse patternover four corresponding geographic sectors, and wherein the first cellis horizontally adjacent to the center cell. The second tier alsoincludes a second cell configured to support a second alternating reusepattern over four corresponding geographic sectors, wherein the secondalternating frequency reuse pattern includes the first alternatingfrequency reuse pattern rotated by ninety degrees. The second cell isvertically adjacent to the center cell, and offset the center cell byhalf an edge.

In another embodiment, a wireless backhaul network includes a first cellconfigured to support a first alternating frequency reuse pattern of afirst channel and a second channel over four corresponding geographicsectors. The four corresponding geographic sectors are represented by asquare pattern. In addition, the network includes a second cellconfigured to support a second alternating reuse pattern over fourcorresponding geographic sectors. The second alternating frequency reusepattern comprises the first alternating frequency reuse pattern, that isrotated by ninety degrees. In addition, the second cell is verticallyadjacent to the center cell. Also, the second cell is offset from thecenter cell by half an edge.

In still another embodiment, a backhaul network includes a plurality ofcells, each of which includes one or more hubs supporting wirelessbackhaul communication over four geographic sectors. The networkincludes a first row of the plurality of cells. More specifically, thefirst row includes a plurality of first cells, each of which isconfigured to support a first alternating frequency reuse pattern of afirst channel and a second channel over four corresponding geographicsectors. In the first row, edges of two adjacent first cells are alignedwithout any offset. In addition, the network includes a second row ofthe plurality of cells. More specifically, the second row includes aplurality of second cells, each of which is configured to support asecond alternating reuse pattern over four corresponding geographicsectors. In the second row, edges of two adjacent second cells arealigned without any offset. Also, the second alternating frequency reusepattern comprises the first alternating frequency reuse pattern that isrotated by ninety degrees. Moreover, the second row is adjacent to thefirst row, such that a corresponding second cell in the second row isadjacent to a corresponding first cell in the first row with an offsetof half an edge of the first cell.

In another embodiment, a method for configuring a backhaul network isdisclosed. The method includes defining two types of cellconfigurations. A first cell is defined that is configured to support afirst alternating frequency reuse pattern utilizing a first channel anda second channel over four corresponding geographic sectors. The firstcell comprises one or more hubs supporting wireless backhaulcommunication over four geographic sectors. In addition, a second cellis defined that is configured to support a second alternating frequencyreuse pattern over four corresponding geographic sectors, wherein thesecond alternating frequency reuse pattern comprises the firstalternating frequency reuse pattern that is rotated by ninety degrees.In addition, the second cell includes one or more hubs supportingwireless backhaul communication over four geographic sectors. A firstcell is deployed. A second cell is also deployed, wherein the secondcell is vertically adjacent to the first cell, and offset the first cellby half an edge.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings which illustrate what is regarded as the preferred embodimentspresently contemplated. It is intended that the embodiments and figuresdisclosed herein are to be considered illustrative rather than limiting.

FIG. 1 is an illustration of a communication network that includes awireless backhaul network, in accordance with one embodiment of thepresent invention.

FIG. 2A is an illustration of a cell of a network implementing awireless backhaul network, in accordance with one embodiment of thepresent invention.

FIG. 2B is an illustration of a backhaul network providing wirelessbackhaul throughout a sector of a cell, in accordance with oneembodiment of the present invention.

FIG. 3 is an illustration of a multi-cell layout, wherein all cells havesimilar frequency reuse patterns.

FIG. 4 is an illustration of a multi-cell deployment model, wherein thehub grid is shifted by a cell radius between two rows of cells, andwhere the frequency reuse patterns between cell rows are rotated byninety-degrees, in accordance with one embodiment of the presentinvention.

FIG. 5 is a flow diagram illustrating a method for deploying amulti-cell deployment model, wherein the hub grid is shifted by a cellradius between two rows of cells, and where the frequency reuse patternsbetween cell rows are differentiated or rotated by ninety-degrees, inaccordance with one embodiment of the present invention.

FIGS. 6A-6C are an illustration of a square cell deployment geometrywireless backhaul network implementing heterogeneous wireless backhaulnetwork expansion techniques in accordance with embodiments of thepresent invention.

FIGS. 7A-7C are an illustration of a tier offset cell deploymentgeometry wireless backhaul network implementing heterogeneous wirelessbackhaul network expansion techniques in accordance with embodiments ofthe present invention.

FIGS. 8A-8C are an illustration of a homogeneous build out of a squarecell deployment geometry wireless backhaul network implementingheterogeneous wireless backhaul network expansion techniques inaccordance with embodiments of the present invention.

FIGS. 9A-9C are an illustration of a homogeneous build out of a tieroffset cell deployment geometry wireless backhaul network implementingheterogeneous wireless backhaul network expansion techniques inaccordance with embodiments of the present invention.

FIG. 10 is an illustration of a heterogeneous cell deployment geometrywireless backhaul network in accordance with embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in more detail to preferred embodiments ofthe present invention, systems and methods for frequency reuse in amulti-cell deployment model of a wireless backhaul network. While theinvention will be described in conjunction with preferred embodiments,it will be understood that they are not intended to limit the inventionto these embodiments. On the contrary, the invention is intended tocover alternatives, modifications and equivalents which may be includedwithin the spirit and scope of the invention.

Embodiments of the present invention provide for frequency reuse in amulti-cell deployment model of a wireless backhaul network, wherein thesame pair of channels are used in a 1:2 frequency reuse pattern. Otherembodiments of the present invention provide the above advantage andalso provide for improved data rates, uniform distribution of the datathroughput (e.g., downlink data rate) peak rate across a single cell,less interference from adjacent sectors in a multi-cell deploymentmodel, less outage at the sector boundaries, and improved carrier tonoise plus interference (CINR) ratios. In addition to or in thealternative to the foregoing, embodiments of the invention provide abackhaul network including a plurality of cells, each of which includesone or more hubs supporting wireless backhaul communication utilizingwireless communication frequency assignments adapted to facilitateexpansion of the backhaul network by maintaining an orthogonal frequencyface relationship between each cell of a cluster of cells having anumber of sectors thereof being expanded and corresponding cell externalto the cluster.

In a communication network that provides connectivity to thetelecommunication infrastructure to an end customer, a base station, anaccess point or a subscriber box form the connection with the endcustomer. The challenge is the connectivity between the base station,access point or subscriber box and the telecommunication infrastructure.This connectivity is often referred to as wireless backhaul. Wirelessbackhaul can be provided by a center node, or hub, that controls thewireless communication with one or more remote nodes, or remotestations. These remote nodes and hub connect small base stations, accesspoints or subscriber boxes to their telecommunications provider. Remotenodes are spread out through a community to wirelessly connect smallbase stations, access points or subscriber boxes to their provider. Ingeneral, remote nodes are paired with a corresponding base station,access point, or subscriber box, and fixed to a point in space. Forinstance, the pair may be deployed on a wall of a building, lamp post,street sign pole, utility pole or any other object that is capable ofsupporting the pair of devices at street level. As such, a wirelessbackhaul network provides an alternative communication platform over themore typical wired connection back to small base stations, access pointsor subscriber boxes through buried or suspended telephone lines.

As a result, as the number of users increase over a particulargeographic area, the network of remote nodes, and corresponding hubsthat support the remote nodes, is scalable to quickly meet the increasein demand. In addition, a layout of remote nodes and corresponding hubsis capable of providing wireless backhaul to small base stations, accesspoints or subscriber boxes that is more economical than a service thatprovides a wired connection to the small base stations, access points orsubscriber boxes. Further, in the fast paced world of conductingbusiness on-the-go, the network of remote nodes is able to providetelecommunication service to small base stations, access points, orsubscriber boxes that cannot be serviced by a fixed-point wiredconnection.

FIG. 1 is an illustration of an exemplary communication system 100 thatincludes a wireless backhaul network, in accordance with one embodimentof the present invention. System 100 generally represents acommunication network implementing one or more wireless backhaulnetworks of embodiments of the present invention, and for purposes ofclarity and illustration may not include all of the components necessaryfor a fully functional communication system.

In addition, communication system 100 supports one or more communicationprotocols suitable for providing communication between one or more endcustomers 160 and their respective telecommunication infrastructure 120,and is not intended to be limited to any one particular communicationprotocol. As an example, system 100 provides for broadband communicationthrough the delivery of packets between various elements and componentsproviding communication between end customers. In addition, the same ordifferent communication protocols may be used between differentcomponents of communication system 100. For instance, the Ethernetprotocol may be used between two components of system 100, while thetransmission control protocol/internet protocol (TCP/IP) standard may beused between another two components of system 100, and further one ofthe IEEE 802.16 substandards or fourth generation (4G) long termevolution (LIE) substandards may be also be used between othercomponents of system 100.

More particularly, embodiments of the present invention are intended toprovide for a wireless backhaul network that is capable of supportingany communication protocol. The wireless backhaul network incommunication system 100 includes one or more aggregation backhaulmodules 110 (hereinafter referred to as “hubs”) that provide access to atelecommunications infrastructure 120 over a wired or wireless interface105. Generally, the telecommunications infrastructure 120 supportstelecommunication providers, that in turn support the linking togetherof various end customers 160. For instance, the telecommunicationsinfrastructure 120 supports one or more governmental or commercialproviders that support telecommunication services for multiple endcustomers 160. As an example, infrastructure 120 may include a wirelesscore network for packet and circuit switch voice or data, as well asother communication networks. As such, the telecommunicationsinfrastructure 120 links together all customers of the communicationsystem 100 such that a customer from one provider may communicate withanother customer from another provider through infrastructure 120.

Each of the hubs 110 support a cluster 130 of one or more remote nodes135 to provide for wireless backhaul. The hub 110 controls communicationwith each of remote nodes 135 within its dedicated cluster 130 of remotenodes, and provides connectivity back to the telecommunicationinfrastructure 120. As will be described below, in embodiments, hub 110is a center hub, a sector hub, or a combination of the above.

Communication with remote nodes 135, either directly between remotenodes or through the telecommunication infrastructure 120, requires thecommunicative coupling of the remote nodes 135 to corresponding hubs 110through a wireless backhaul network. That is, the backhaul networkcommunicatively couples a remote station 135 with a corresponding hub110, which in turn provides for communicative coupling back to thetelecommunication infrastructure 120. More specifically, in oneembodiment for increased scalability the backhaul network provides fornon-line-of-sight (NLOS) wireless communications between a remote node135 and a corresponding hub 110.

As shown in FIG. 1, a telecommunications provider utilizes a backhaulnetwork to provide communication to its end customers 160. For purposesof clarity and illustration, a picocell 139, which is an example of asmall base station, access point or subscriber box, provides forwireless communication to one or more end customers 160, that may or maynot be mobile. Picocell 139 may support third generation (3G), fourthgeneration (4G), Wi-Fi and other types and generations of communicationnetworks and/or standards. Given that a picocell 139 as a system is moremanageable (typically the size of a laptop computer or small suitcase)than macrocell base stations providing connectivity to remote units(e.g., mobile phones, laptops, personal digital assistants, phones,etc.), picocell deployment within a geographic area provides forincreased coverage in areas that are difficult to service, and providesfor increased data throughput in higher traffic areas that needincreased bandwidth to support its customers. The configuration shown inFIG. 1 utilizing wireless connectivity to end customers through apicocell network may be achieved at a more attractive cost than otherservices providing connectivity, or last mile coverage, to endcustomers. For instance, because of its smaller size, typical deploymentof one or more picocells may occur on a wall of a building, lamp post,street sign pole, utility pole or any other object that is capable ofsupporting the device at street level.

While embodiments of the present invention are described within thecontext of providing a wireless backhaul network providing picocellcoverage, other embodiments of the present invention support backhaulnetworks that communicatively couple end-customers of the remotestations 135 to their telecommunication providers through any type ofplatform, to include macrocells, femtocells, superfemtocells, outdoorfemtocells, access points, compact base stations, etc. Embodiments ofthe invention may, for example, provide wireline links to the endcustomers, such as by providing Ethernet network links coupled to aremote node herein (e.g., using a router, switch, or other Ethernetnetwork device in place of a picocell shown in FIG. 1), to therebyprovide wireless backhaul for a wireline network. Of course,combinations of wireless and wireline end customer equipment may besupported according to embodiments of the invention.

In addition, each picocell 139 is communicatively coupled to acorresponding remote station 135. This may be achieved through a wiredor wireless connection. In one implementation, a remote station 135 andpicocell are deployed together in a single location, such as on alamppost. In one implementation, because of their proximity, the devicesmay be coupled together through a wired connection to provide the bestperformance over a wired connection. In other instances, where a wiredconnection is not possible, a wireless connection may be implemented. Asa result, the end customer 160 is communicatively coupled to itstelecommunication provider through a path including a correspondingpicocell 139, remote station 135, wireless backhaul link to acorresponding hub 110, and through the telecommunication infrastructure120.

FIG. 2A is an illustration of the deployment of clusters of remote nodesin a cell 250 in a network 200A providing wireless backhaul throughoutcell 250, in accordance with one embodiment of the present invention.The cell 250 in FIG. 2A provides a more detailed illustration of therelationship between hubs and remote nodes provided in FIG. 1. Morespecifically, the cell 250 defines a geographic area over which awireless backhaul network is supported. That is, cell 250 defines thecoverage area in which wireless backhaul is available as supported byone or more hubs and remote nodes. More specifically, cell 250 isdivided into four sectors, sector 250A in the upper right corner, sector250B in the upper left corner, sector 250C in the lower left corner, andsector 250D in the lower right corner. As the number of customersincreases, or as demand for bandwidth increases, more hubs and remotenodes defining one or more cells can be added in a scalable fashion toquickly service the increase in customers and/or demand.

As shown in FIG. 2A, cell 250 shows a wireless backhaul coverage areathat includes three roads 295, 297, and 299. The area defined by cell250 is representative of any area that requires wireless backhaulservices. For instance, the area may be a downtown region of a small orlarge town, a suburban area populated by residential homes and smallretail businesses, a remote area that is sparsely populated, or acombination of the above.

In particular, cell 250 includes a center hub 210 of a backhaul network200A that supports wireless backhaul throughout at least cell 250. Itshould be appreciated that a cell, or a sector thereof, is not requiredto have a hub (and correspondingly, need not have remotes deployedtherein) if there is insufficient traffic or coverage is otherwise notneeded. However, the cell and sector(s) thereof should be planned toensure optimal performance when, in the future, a hub and remotes aredeployed. Such advanced planning of frequency reuse is providedaccording to embodiments of the present invention.

As shown, center hub 210 is approximately located in the center of cell250 so that all sectors of cell 250 may be supported equally. The centerhub 210 supports one or more clusters of remote nodes in order toprovide wireless backhaul coverage in the geographic area defined bycell 250. For instance, sector 250A defines a geographic area in cell250 over which coverage is provided for wireless backhaul by thecombination of center hub 210 and a cluster 235A of remote nodes.Cluster 235A includes remote node 235A-1 and remote node 235A-2. As anexample, sector 250A may be a mountainous area traversed by road 297,wherein remote nodes in the cluster 235A are positioned to providemobile service to users traveling on road 297. In addition, sector 250Bdefines a geographic area in cell 250 over which coverage is providedfor wireless backhaul by center hub 210 and a cluster 235B of remotenodes. Cluster 235B includes one remote node. Sector 250B may be an areawith concentrated usage areas in which the demand for service can becovered using one remote node in cluster 235B. Further, sector 250Cdefines a geographic area in cell 250 over which coverage is providedfor wireless backhaul by center hub 210 and a cluster 235C of remotenodes. Cluster 235C includes three remote nodes. As an example, sector250C may be a residential area. Also, sector 250D defines a geographicarea in cell 250 over which coverage is provided for wireless backhaulby center hub 210 and a cluster 235D of remote nodes. Cluster 235Dincludes four remote nodes. As an example, sector 250D may be a morepopulated area, such as a downtown area, or major commute corridor.

It is important to note that the number of remote nodes in each clusterproviding wireless backhaul to sectors 250A-D is not fixed. Forinstance, though cluster 235A providing. wireless backhaul coverage tosector 250A includes two remote nodes, remote nodes may be added ordeleted depending on the demand for bandwidth by end customers. That is,if there is an increase in demand, more remote stations may be deployedinto sector 250A, or if already deployed in anticipation may be broughton-line into the wireless backhaul network 200A. As the number ofcustomers grows, or as demand for bandwidth grows, throughout ageographic area, more remote nodes can be added to a cluster in ascalable fashion to quickly service the increase in customers and/ordemand.

In one embodiment, center hub 210 supports wireless backhaul over thegeographic area defined at least by cell 250. That is, center hub 210controls and coordinates wireless backhaul with one or more of theclusters of remote nodes 235A-D in cell 250. As such, center hub 210 isconfigured to handle wireless backhaul traffic to one or more sectorsthroughout cell 250. In other embodiments, center hub 210 includes oneor more sector hubs that are dedicated to control and coordinatewireless backhaul with a corresponding cluster of remote nodes in aparticular sector. For instance, as shown in FIG. 2A, center hub 210includes sector hubs 210A-210D, where sector hub 210A provides wirelessbackhaul to cluster 235A in sector 250A, sector hub 210B provideswireless backhaul to cluster 235B in sector 250B, sector hub 210Cprovides wireless backhaul to cluster 235C in sector 250C, and sectorhub 210D provides wireless backhaul to cluster 235D in sector 250D. Instill other embodiments, a sector hub provides wireless backhaul to oneor more clusters of remote nodes in one or more sectors in cell 250.

FIG. 2B is an illustration of part of a network 200B providing wirelessbackhaul throughout sector 250A of cell 250, in accordance with oneembodiment of the present invention. As shown, sector hub 210A of centerhub 210 provides dedicated wireless backhaul throughout sector 250A incombination with cluster 235A of remote nodes. Alternatively, aspreviously described, the functions provided by sector hub 210A may beprovided solely by center hub 210.

Sector hub 210A includes, in part, radio frequency (RF) equipment210A-1, as well as other control units for controlling wireless backhaultraffic between the sector hub 210A and the cluster of remote nodes235A. Sector hub 210A also includes one or more antennas 210A-2 thatspread a corresponding beam pattern 270 throughout sector 250A. The oneor more antennas 210A-2 are configured such that the beam pattern 270 isfocused to primarily provide coverage within sector 250A. For instance,the main lobe of beam pattern 270 may be concentrated within sector250A.

As shown in FIG. 2B, one or more remote nodes are located within sector250A and interact with sector hub 210A to provide wireless backhaulcommunication. For illustration, two remote nodes 235A-1 and 235A-2 areshown in cluster 235A, although any number of remote nodes may be used.The remote nodes in cluster 235A in combination with sector hub 210Aprovide wireless backhaul throughout sector 250A. The remote nodes incluster 235A are deployed in a particular pattern to achieve the bestsignal coverage of the demand exhibited within sector 250A. Forinstance, remote nodes 235A-1 and 235A-2 may be deployed near road 297to provide wireless backhaul coverage in support of end customers whomay be traveling on road 297. Additional remote nodes may be includedwithin sector 250A to provide even better wireless backhaul coverage.

FIG. 3 is an illustration of a multiple-cell (multi-cell) deployment300, wherein all cells have similar frequency reuse patterns. A cellconsists of multiple sectors that are deployed throughout a geographicarea. In the deployment 300 of multiple cells, cell 310 isrepresentative of one of the cells, and illustrates a backhaul networkthat includes a center hub and several remote nodes that are spreadacross four geographic sectors. In general, center hub is approximatelylocated in a center location 315 of cell 310, depending on constraintsdue to geographic and physical environment conditions. Center hub mayinclude one or more sector hubs, each of which is dedicated to providingwireless backhaul to a corresponding sector of the cell 310. Each sectoris capable of supporting one or more remote nodes. Cell 310 is generallyrepresented by a square in FIG. 3. More specifically, the footprint forcell 310 represents a geographic area over which center hub and/orsector hubs and their corresponding remote nodes form a backhaulnetwork.

In addition, as shown in FIG. 3, cell 310 includes an alternating 1:2frequency reuse pattern, where two frequency bands or channels (e.g.,channels 1 and 2) are reused within a single cell, such as cell 310, toimprove the spectral efficiency of the available bandwidth. Inparticular, the two channels are alternated between adjacent sectors ofcell 310 in an effort to reduce interference problems. For consistencythroughout this Application, the frequency reuse pattern is describedstarting with the sector located in the top-right corner of the cell. Assuch, starting with sector 313 in the top-right corner of cell 310,moving in a counter-clockwise direction 319, the 1:2 frequency reusepattern is 1-2-1-2.

More specifically, cell 310 is used in a repeating pattern throughoutthe multi-cell deployment 300. For instance, a row of cells comprisesone or more cells 310 configured such that two adjacent cells 310 in therow share a common edge. For instance, in row 330, a common edge 337 isshared by cells defined by hub 334 and hub 339. In addition, a column ofcells comprises one or more cells 310 configured such that two adjacentcells in the column also share a common edge. As such, the hubs in themulti-cell deployment 300 approximately form a uniform grid.

It is understood that the deployment 300 is merely representative of thelayout of multiple cells 310 over a geographic area. In practice, thephysical layout of hubs of corresponding cells may vary slightly fromthat depicted in deployment 300 depending on physical and geographiclimitations. Additionally, some sectors in deployment 300 may not bepopulated with corresponding sector hubs and remote nodes. That is, in aparticular cell in deployment 300 some sectors may have wirelessbackhaul coverage while other sector or sectors are without backhaulcoverage. Further, some cells in deployment 300 may not be populatedwith corresponding center hubs and remote nodes. In that case, acorresponding cell does not have backhaul coverage. Holes in backhaulcoverage within cells or sectors of a cell will often occur while theoverall wireless backhaul network is being developed.

Since each channel of frequencies is used twice in a cell 310, therewill be interference among sectors of the same cell in a single celldeployment model, thereby reducing the signal to noise ratio, or moreparticularly, the carrier to noise plus interference ratio (CINR). Thistranslates to lower data rates, and overall lower throughput in the cell310. Additionally, although FIG. 3 illustrates a 1:2 frequency reusepattern in the multi-cell deployment 300, the interference problemexists in other frequency reuse patterns, such as a 1:1 frequency reusepatter, or 1:3 frequency reuse pattern.

In addition, the interference is further evidenced in the multi-celldeployment model 300. For instance, in a center cell defined by centerlocation 340, there is interference that is, in part, due to center hubconfigurations of neighboring cells that lie on a line defining themid-line of a corresponding sector, or a bore sight of the center cell.Neighboring cells include those defined by center location 334 andcenter location 345. As an example, sectors supporting channel “2” lieon a diagonal line Z-Z of the multi-cell deployment 300 running from thetop left corner to the lower right corner and through the center hublocated at center location 340, and other hubs located at centerlocations 334 and 345. As such, since sectors with the same frequencies(channel “2”) are located on the diagonal of the cell layout supportedby center cell defined by center location 340, any remote stationlocated on the bore sight of the center cell on line Z-Z will see morethan one hub from neighboring cells all supporting the same channel.This leads to CINR degradation, especially on the edges and bore sightsof the sectors of the center cell defined by center location 340.

FIG. 4 is an illustration of a multi-cell deployment 400, wherein thehub grid is shifted by a cell radius between two cells and/or two rowsof cells, and where the frequency reuse patterns between cell rows arerotated by ninety-degrees, in accordance with embodiments of the presentinvention. In comparison to the uniform deployment of cells in FIG. 3,the multi-cell deployment 400 of FIG. 4 exhibits reduced interferencebetween hubs of neighboring cells, thereby increasing CINR, in oneembodiment. In addition, the multi-cell deployment 400 having a 1:2frequency reuse pattern outperforms other frequency reuse patternsacross the same frequency channels in both single cell and multi-cellscenarios, in other embodiments. Further, in still another embodiment ofthe present invention, the multi-cell deployment 400 exhibited in FIG. 4exhibits a more uniform distribution of data throughput (e.g., downlink)peak rate across a cell, compared to other frequency reuse patterns onthe same frequency channels.

In the deployment 400 of multiple cells, there are two types of cellsutilized: a first cell 410 and a second cell 420, each of whichillustrate a corresponding backhaul network including a center locationpopulated with a center hub, that may include one or more sector hubs,and one or more remote nodes spread throughout sectors of acorresponding cell. In particular, the frequency pattern of the secondcell 420 is similar in configuration to the frequency pattern of thefirst cell 410, but is rotated by ninety degrees within deployment 400,as will be described below.

First cell 410 illustrates part of a backhaul network that includes acenter hub and/or one or more sector hubs approximately located atcenter location 415, and one or more remote nodes spread across fourgeographic sectors. That is, each sector is capable of supporting one ormore remote nodes for purposes of forming part of a backhaul network.First cell 410 is generally represented by a square in FIG. 4. Morespecifically, the footprint for cell 410 represents a geographic areaover which a center hub approximately located at a center location 415communicates with corresponding remote nodes located within the sectorsof the cell 410 in order to form a backhaul network.

In one embodiment, center hub at center location 415 includes one ormore directional antennas to form corresponding beam patterns into eachof the sectors. For instance, in one implementation a center and/orsector hub at center location 415 includes a 90 degree horizontalbeamwidth antenna having 16 dBi gain that radiates a beam pattern intoone of the four sectors of the first cell 410.

In addition, a remote node located in one of the sectors of the firstcell 410 includes a highly directional antenna pointed to acorresponding center and/or sector hub to form a communicative linkbetween the two nodes for providing wireless backhaul. In one instance,the hub to which the antenna is pointed is at the center location 415 ofthe cell. In another instance, the hub to which the antenna of theremote station is pointed is located in an adjacent cell. As an example,the remote antenna may form a 15 degree antenna beam with 18 dBi gain.The antennas described above are equally applicable to remote nodeconfigurations of the second cell 420.

In addition, first cell 410 is representative of a first 1:2 alternatingfrequency reuse pattern, where two frequency bands or channels arereused within a single cell to improve the spectral efficiency of theavailable bandwidth, and is used in the multi-cell deployment 400. Inparticular, the two channels are alternated between adjacent sectors ofcell 210 in an effort to reduce interference problems. For instance,sector 413 is supported by a first channel (represented by the number“I”), and adjacent sectors in cell 410 to sector 413 are supported by asecond channel (represented by the number “2”). Moving in acounter-clockwise direction 419 and starting with sector 413 in thetop-right corner of cell 410, the 1:2 frequency reuse pattern is1-2-1-2.

Also, multi-cell deployment 400 includes a second cell 420 that isrepresentative of a second alternating frequency reuse pattern. Cell 420is generally represented by a square footprint including four geographicsectors, each of which may support one or more remote nodes to form abackhaul network with a corresponding hub. In addition, as shown in FIG.4, the second alternating frequency reuse pattern exhibits a 1:2frequency reuse pattern, where two frequency bands or channels arealternated between adjacent sectors within the second cell 420. Moreparticularly, the second alternating frequency reuse pattern is similarto the first alternating frequency reuse pattern of the first cell 410,but is rotated by ninety degrees, such that the first channel is now inthe top left sector 421 and lower right sector 425. As such, beginningwith the upper right sector 423 of second cell 420 and moving over thefour sectors in a counterclockwise direction, the second alternatingfrequency reuse pattern provides a 2-1-2-1 pattern, again where a firstchannel “1” and a second channel “2” alternate between adjacent sectors.

In one embodiment, the frequency bandwidth allocated to the first cell410 and the second cell 420 is a combined total of approximately 20 MHz.The total bandwidth is allocated equally between the two channels. Assuch, the first channel includes a bandwidth of 10 MHz, and the secondchannel includes a bandwidth of 10 MHz. In one embodiment, the firstchannel and the second channel do not have contiguous frequencies.

In another embodiment, the combined frequency bandwidth allocated to thefirst cell 410 and the second cell 420 combined is less than 20 MHz. Assuch, the first channel could include a bandwidth of 3, 5, 7 or 10 MHz(as examples), and the second channel includes a bandwidth of 3, 5, 7 or10 MHz (as examples). In embodiments, the total bandwidth may or may notbe allocated equally between the two channels. Also, in one embodiment,the first channel and the second channel do not have contiguousfrequencies.

In still another embodiment, the combined frequency bandwidth allocatedto both the first cell 410 and the second cell 420 is more than 20 MHz.As such, the first channel includes a bandwidth of 3, 5, 7, 10, 15 or 20MHz (as examples), and the second channel includes a bandwidth of 3, 5,7, 10, 15 or 20 MHz (as examples). In embodiments, the total bandwidthmay or may not be allocated equally between the two channels. Also, inone embodiment, the first channel and the second channel do not havecontiguous frequencies.

More particularly, the configuration of hubs in the backhaul networkincludes a first cell and a second cell, as previously described, inaccordance with one embodiment of the present invention. As an example,in FIG. 4, one first cell 410 includes a center hub, that may includeone or more sector hubs, and is centrally located approximately atcenter location 430. This first cell may also be referred to as thecenter cell, and is outlined by a bolded and solid line. In addition,the backhaul network layout includes one second cell 420 including acenter hub, that may include one or more sector hubs, wherein the secondcell 420 is centrally located approximately at center location 440, andis outlined by a bolded and dotted line.

Also, the second cell located at center location 440 is verticallyadjacent to the center cell defined by center location 430. That is, asshown in FIG. 4, the second cell located approximately at centerlocation 440 is located geographically above the center cell locatedapproximately at center location 430.

In addition, the second cell is offset the first cell by a cell radius.More particularly, a vertical line D-D through the center hub located atcenter location 440 of the second cell is offset from a parallelvertical line A-A through the center hub located at center location 430of the first cell by a cell radius 485 (i.e., cell 440 is offsethorizontally with respect to call 430), in one embodiment. As shown inFIG. 4, the cell radius 485 is one-half of the full edge 480 of arepresentative cell. Put another way, cell radius 485 is half thedistance between the center locations of two adjacent cells in a row ofcells, such as the row defined by line B-B, in another embodiment. Assuch, instead of lying on a vertical line A-A that goes through thecenter location 430 of the first cell, the center hub located at centerlocation 440 of the second cell is offset from the vertical line A-A bycell radius 485, and is located on vertical line D-D. Put another way,the second cell 420 as defined by center location 440 shares one-half ofa full edge with the first cell 410 defined by center location 430, inanother embodiment.

It is important to note that the second cell 420 that is verticallyadjacent to the first cell 410 or center cell defined by center location440 could be located in anyone of four locations. Specifically, thesecond cell 420 could be vertically located above the center cell andoffset to the right by a cell radius 485 to include center location 440,as described above. In addition, the second cell 420 could be verticallylocated above the center cell defined by center location 430 and offsetto the left by a cell radius 485 to include center location 443. Also,the second cell 420 in the backhaul network could be vertically locatedbelow the center cell defined by center location 430 and offset to theright by a cell radius 485 to include center location 445. Further, thesecond cell 420 in the backhaul network could be vertically locatedbelow the center cell defined by center location 430, and offset to theleft by a cell radius 485 to include center location 447.

In another embodiment, the multi-cell deployment 400 illustrates anotherbackhaul network. The backhaul network includes a plurality of cells,and more specifically, includes first cells 410 and second cells 420. Aspreviously described, each of the first or second cells comprises acenter hub, that may include one or more sector hubs, supportingwireless backhaul communication over four corresponding geographicsectors.

Further, the backhaul network includes a first row 460 of the pluralityof cells. The first row 460 comprises a plurality of first cells 410previously described. That is, each of the first cells 410 is configuredto support a first alternating frequency reuse pattern of a firstchannel and a second channel over four corresponding geographic sectors.Moreover, adjacent first cells 410 in the first row 460 are alignedwithout any offset. That is, edges of two adjacent cells are alignedwithout any offset, such that the two adjacent first cells 410 share anedge.

Also, center hubs in the first cells 410 of the first row 460 lieapproximately on a horizontal line (e.g., line B-B). For instance, asshown in FIG. 4, the center cell defined by center location 430 isadjacent to another first cell 410 located directly to the right, and toanother first cell 410 located directly to the left. Row 460 includesother first cells 410 (not shown) following the same configurationdescribed above, in one embodiment.

In addition, the backhaul network includes a second row 450 of theplurality of cells. The second row comprises a plurality of second cells420 previously described. That is, each of the second cells isconfigured to support a second alternating frequency reuse pattern overfour corresponding geographic sectors. The second alternating frequencyreuse pattern comprises the first alternating frequency reuse patternthat is rotated by ninety degrees. Moreover, adjacent second cells 420in the second row 450 are aligned without any offset. That is, edges ofthe two adjacent cells are aligned without any offset, such that the twoadjacent second cells 420 share an edge. Also, center hubs in the secondcells of the second row 450 lie approximately on a horizontal line, thatis approximately parallel to line B-B. For instance, as shown in FIG. 4,the cell defined by center location 443 is adjacent to another secondcell 420 located to the right that is defined by center location 440.Row 450 includes additional second cells 420 (not shown) following thesame configuration described above, in one embodiment.

Further, the second row 450 is adjacent to the first row 460. As shownin FIG. 4, second row 450 is located above first row 460, but could belocated below first row 460, as evidenced by row 470 that also includesa plurality of second cells 420. In addition, the second row 450 isoffset by a cell radius 485 from the first row 460, such that acorresponding second cell in the second row 450 is adjacent to acorresponding first cell 410 in the first row 460, and is offset by acell radius 485, or offset by half a full edge 480 of the correspondingfirst cell 410 or second cell 420. More specifically, the second cell420 in the second row 450 is vertically adjacent to a correspondingfirst cell 410 in the first row 460 (such as the second cell defined bycenter location 440 and the first cell defined by center location 430).Put another way, a vertical line D-D through the center location 440 ofthe second cell 420 in the second row 450 is offset from a vertical lineA-A through the center location 430 of the corresponding first cell 410in the first row 460 by a cell radius 485. This relationship is repeatedfor corresponding first cells 310 and corresponding second cells 320 inboth first and second rows 460 and 450, respectively.

The backhaul network includes a third row of cells, in one embodiment.The third row comprises another plurality of second cells 420, each ofwhich is configured to support the second alternating reuse pattern overfour corresponding geographic sectors. Moreover, adjacent second cells420 in the third row 470 are aligned without any offset. That is, edgesof the two adjacent cells are aligned without any offset, such that thetwo adjacent second cells 420 share an edge. Also, center hubs in thecells of the third row 470 lie approximately on a horizontal line, thatis approximately parallel to lines B-B and C-C. For instance, as shownin FIG. 4, the second cell defined by center location 447 is adjacent toanother second cell 420 located to the right that is defined by centerlocation 445. Row 470 includes additional second cells 420 (not shown)following the same configuration described above, in one embodiment.

In addition, the third row 470 is adjacent to the first row 460, suchthat the first row 460 is between the second row 450 and the third row470. A corresponding second cell 420 in the third row 470 is aligned toa corresponding first cell 410 in the first row 460 with an offset of acell radius 485, or half an edge of the first cell 410.

As shown in FIG. 4, third row 470 is located below first row 460. Inaddition, the third row 470 is offset by a cell radius 485 from thefirst row 460, such that a corresponding second cell in the third row470 is adjacent to a corresponding first cell 310 in the first row 460,and is offset by a cell radius 485, or offset by half a full edge 480 ofthe first cell 410 or second cell 420. More specifically, the secondcell 420 in the third row 470 is vertically adjacent to a correspondingfirst cell 410 in the first row 460 (such as the second cell 420 definedby center location 447 and the first cell 410 defined by center location430). For the offset, the center hub(s) of second cells 420 in the thirdrow 470 is offset from the center hub(s) of corresponding first cells410 in the first row 460 by a cell radius 485. Put another way, avertical line D-D through the center location 445 of the second cell 420in the third row 470 is offset from a vertical line A-A through thecenter location 430 of the corresponding first cell 410 in the first row460 by a cell radius 485. This relationship is repeated forcorresponding first cells 410 and corresponding second cells 420 in bothfirst and third rows.

Further, the backhaul network includes a fourth row of cells (notshown), in one embodiment. The fourth row comprises another plurality offirst cells 410, each of which is configured to support the firstalternating reuse pattern over four corresponding geographic sectors.Moreover, adjacent first cells 410 in the fourth row (not shown) arealigned without any offset. That is, edges of the two adjacent cells arealigned without any offset, such that the two adjacent first cells 410share an edge. Also, hubs in the cells of the fourth row lieapproximately on a horizontal line that is approximately parallel toline B-B and to line C-C. Additionally, the fourth row is adjacent tothe second row 450, such that the second row 450 is between the firstrow 460 and the fourth row (not shown), and wherein a correspondingfirst cell in the fourth row is aligned to a corresponding second cellin the second row 450 with an offset of a cell radius 485, or half afull edge 480, as previously described. In addition, the fourth rowcould be adjacent to the third row 470, such that the third row 470 isbetween the first row 460 and the fourth row (not shown), and wherein acorresponding first cell in the fourth row is aligned to a correspondingsecond cell in the third row 470 with an offset of a cell radius 485, orhalf a full edge 480, as previously described.

In another embodiment, the multi-cell deployment 300 illustrates anotherbackhaul network. The backhaul network includes a plurality of cells,and more specifically, includes first cells 410 and second cells 420. Aspreviously described, each of the first or second cells comprises one ormore hubs supporting wireless backhaul communication over fourcorresponding geographic sectors. The backhaul network is comprised oftwo or more tiers of cells.

For instance, a first tier of cells comprises a center cell that isconfigured to support a first alternating frequency reuse pattern of afirst channel and a second channel over four corresponding geographicsectors. As shown in FIG. 4, the center cell comprises a first cell 410,and includes center location 430.

A second tier of cells surrounds the first tier. In particular, thesecond tier includes a first cell 410 configured to support the firstalternating reuse pattern, and wherein the first cell 410 is locatedhorizontally adjacent to the center cell defined by center location 430.In one embodiment, the second tier includes both the first cells 410located to the right and left of the center cell defined by centerlocation 430, such as the first cell 410 defined by center location 435and first cell 410 defined by center location 437.

In addition, the second tier of cells includes at least one second cell420 that is configured to support the second alternating frequency reusepattern. As shown in FIG. 4, the second cell 420 is located verticallyadjacent to the center cell defined by center location 430. In oneembodiment, the second cell 420 is located above and below the centercell. Further, the second cell 420 is offset from the center cell by acell radius 485, as previously described, and for example, such that thesecond cell 420 and the center cell share one half of a full edge 480 ofa representative cell. As such, the second tier could include secondcells defined by hubs 440, 443,445, and 447. In one embodiment, thesecond tier includes each of the cells defined by hubs435,437,440,443,445, and 447.

As a result, the second tier of cells includes 6 cells comprising bothfirst cells 410 and second cells 420, in one embodiment. Extending thetier model, the backhaul network includes a third tier of cells of 12cells (not shown) surrounding the second tier of cells, and comprisesboth first cells 410 and second cells 420 that maintain the cellconfiguration and layout described above.

It is understood that the deployment 400 is merely representative of thelayout of multiple cells over a geographic area. In practice, thephysical layout of center hubs of corresponding cells may vary slightlyfrom that depicted in deployment 400 depending on physical andgeographic limitations. Additionally, in each of the embodimentsdescribed above for backhaul networks, some sectors in deployment 400may not be populated with corresponding sector hubs and remote nodes.That is, in a particular cell in deployment 400 some sectors may havewireless backhaul coverage while other sector or sectors are withoutbackhaul coverage. Further, some cells in deployment 400 may not bepopulated with corresponding center hubs and remote nodes. In that case,a corresponding cell does not have backhaul coverage. Holes in backhaulcoverage within cells or sectors of a cell will often occur while theoverall wireless backhaul network is being developed.

In each of the embodiments described above for backhaul networks, CINRdegradation is greatly reduced along sector bore sights, and alongvertical edges of sectors for a corresponding cell. This is mainly dueto the offset of hubs of neighboring cells, since interference stemsmostly from the sidelobe of a corresponding beam pattern radiating intoone of those sectors, and not from the main beam. For instance, hubsbetween first and second tiers do not lie on any of the diagonals of thecenter cell defining the first tier, wherein the diagonals are formedbetween the corners of the center cell and the center location that isoccupied by the hub. As such, hubs for neighboring cells in the secondtier do not lie on any of these diagonals, thereby reducing interferencebetween beam patterns of center hubs in the first and second tier.

FIG. 5 is a flow diagram 500 illustrating a method for deploying amulti-cell deployment model, wherein the hub grid is shifted by a cellradius between two rows of cells, and where the frequency reuse patternsbetween cell rows are rotated by ninety-degrees, in accordance with oneembodiment of the present invention. The method outlined in FIG. 5 isimplementable for deploying various embodiments of the multi-celldeployment 400 illustrated in FIG. 4, in accordance with embodiments ofthe present invention.

The method includes defining 510 a first cell (e.g., cell 410) thatincludes a center hub, that may include one or more sector hubs, and oneor more remote nodes spread across four geographic sectors. Also, thefirst cell is configured to support a first alternating frequency reusepattern, previously described, that utilizes a first channel and asecond channel over the four corresponding geographic sectors. Thefootprint for the first cell represents a geographic area over which thecenter hub extends corresponding beam patterns for communication withcorresponding remote nodes located within corresponding sectors deployedin a first cell in order to form a backhaul network.

The method also includes defining 520 a second cell (e.g., cell 420)that includes a center hub, that may include one or more sector hubs,and one or more remote nodes spread across four geographic sectors.Also, the second cell is configured to support a second alternatingfrequency reuse pattern, previously described. Specifically, the secondalternating frequency reuse pattern comprises the first alternatingfrequency reuse pattern that is rotated by ninety degrees. The footprintfor the second cell represents a geographic area over which the centerhub extends corresponding beam patterns for communication withcorresponding remote nodes located in corresponding sectors deployed ina second cell in order to form a backhaul network.

In addition, the first cell is deployed 530 over a geographic area. Thatis, the center hub of the first cell is deployed with one or moredirectional antennas that form corresponding beam patterns into each ofthe four sectors defining the geographic area. As such, the center hubis able to communicate with one more remote nodes spread throughout foursectors of the first cell to form a backhaul network.

Further, the second cell is deployed 540 over a geographic area. Thatis, a corresponding center hub of the second cell is deployed with oneor more directional antennas that form corresponding beam patterns intoeach of the four sectors defining the geographic area. As such, thecenter hub of the second cell is able to communicate with one or moreremote nodes spread throughout four sectors to form a backhaul network.

In addition, the second cell is vertically adjacent to the first cell.That is, the second cell is located geographically above or below thecenter cell in a vertical direction. In addition, the second cell isoffset from the first cell by a cell radius, or one-half a full edge ofrepresentative cell, as previously described. That is, the second cellcould be offset to the left or right, and above or below the first cell.As such, the first cell and the second cell share one half of a fulledge of a respective one of the cells.

The backhaul network formed by the method outlined in FIG. 5 isextendable to create rows of cells. In particular, a first row isdeployed, wherein the first row comprises a plurality of first cells,and includes the first cell that is deployed. Adjacent first cells inthe first row are aligned without any offset. That is, edges of the twoadjacent cells are aligned without any offset, such that the twoadjacent first cells share an edge. Also, center hubs in the cells ofthe first row lie approximately on a horizontal line.

In addition, the backhaul network is extendable to create another row ofcells. In particular, a second row is deployed, wherein the second rowcomprises a plurality of second cells, and includes the second cell thatis deployed. Adjacent second cells in the second row are aligned withoutany offset. That is, edges of the two adjacent cells are aligned withoutany offset, such that the two adjacent second cells share an edge. Also,center hubs in the cells of the second row lie approximately on ahorizontal line, that is approximately parallel to the horizontal linedefined as intersecting center hubs for first cells in the first rowabove.

Further, the second row is deployed adjacent to the first row. Also, thesecond row is offset by a cell radius from the first row, such that acorresponding second cell in the second row is adjacent to acorresponding first cell in the first row, and is offset by a cellradius, such that the second cell and the first cell share one half of afull edge of a representative cell.

Moreover, a third row is deployed that comprises another plurality ofsecond cells. Edges of two adjacent second cells in the third row arealigned without any offset. In addition, the third row is adjacent tothe first row, and opposite the second row such that the first row isbetween the second and third rows. Also, the third row is offset by acell radius from the first row, such that a corresponding second cell inthe third row is adjacent to a corresponding first cell in the firstrow, and is offset by a cell radius, as previously described. Forinstance, a second cell in the third row and a first cell in the firstrow share one half of a full edge of a representative cell.

Extending the deployment further, a fourth row is deployed thatcomprises another plurality of first cells. Edges of two adjacent firstcells in the fourth row are aligned without any offset. In addition, thefourth row is adjacent to the third row, and opposite the first row,such that the third row is between the fourth and the first rows. Also,the fourth row is offset by a cell radius from the third row, such thata corresponding first cell in the fourth row is adjacent to acorresponding second cell in the third row, and is offset by a cellradius, as previously described. For instance, a corresponding firstcell in the fourth row and a corresponding second cell in the third rowshare one half of a full edge of a representative cell.

Frequency reuse patterns, such as one or more of the foregoing exemplaryfrequency reuse patterns, may be utilized in accordance with embodimentsof the invention to facilitate frequency planning for initialdeployment, build out, and expansion (e.g., increased sectorization andchannel reuse to provide increased communication capacity and/or morefrequency robustness) in wireless backhaul networks which include aplurality of cells as described herein. As discussed above, embodimentscomprise a plurality of cells providing wireless backhaul communicationimplementing a predetermined wireless frequency reuse pattern providingalternating utilization of a plurality of wireless communicationfrequencies by the cells of the backhaul network. The cell deploymentgeometry and frequency assignments are preferably made to accommodatethe aforementioned expansion within the wireless backhaul network, suchas to facilitate expansion of cell configurations from omni-directionalto bi-sectored, from bi-sectored to quad-sectored, from quad-sectored tooctal-sectored, etc. as demand, usage patterns, and/or other conditionschange.

In accordance with embodiments of the invention, a plurality of hubs aredisposed in a predetermined cell deployment geometry to providecommunication services within a composite service area. Cells, such asthose of the exemplary embodiments of FIGS. 6A and 7A, may comprise oneor more sectors that are deployed throughout a geographic area. Ingeneral, a hub is approximately located in a center location of a cell,depending on constraints due to geographic and physical environmentconditions. Such a hub may include one or more sector hubs, each ofwhich is dedicated to providing wireless backhaul to a correspondingsector of the cell. Each such sector is capable of supporting one ormore remote nodes. The footprint for a cell, such as shown in FIGS. 6Aand 7A, represents a geographic area over which the hub, or the sectorhubs thereof, provides wireless communications for remote nodes servedby the wireless backhaul network. FIG. 6A, for example, shows wirelessbackhaul network 600 including hubs 601-616 disposed in a square celldeployment (i.e., cell centers aligned in rows and columns) geometry todefine respective cells 621-636, wherein cells 621-636 cooperate toprovide communication services within the composite service area ofwireless backhaul network 600. Similarly, FIG. 7A shows wirelessbackhaul network 700 including hubs 701-716 disposed in a tier offsetcell deployment geometry (cells of different rows of cells are adjacentbut center offset by half an edge) to define respective cells 721-736,wherein cells 721-736 cooperate to provide communication services withinthe composite service area of wireless backhaul network 700.

As can be seen in the exemplary embodiments of FIGS. 6A and 7A, thecells of the wireless backhaul networks implement alternating frequencyassignments, as described herein. In particular, two frequency bands orchannels (e.g., channels 1 and 2) are reused within the wirelessbackhaul network, wherein the two channels are alternated betweenadjacent cells in an effort to reduce interference problems. As will bebetter understood from the discussion which follows, cells of thepresent invention which are expanded to multi-sectored cells themselvesimplement an alternating frequency reuse pattern, where the twofrequency bands or channels (e.g., channels 1 and 2) are reused within asingle cell, such as to improve the spectral efficiency of the availablebandwidth.

The alternating frequency assignments provide orthogonal frequency faces(i.e., adjacent cell edges, wherein the cells having the adjacent celledges utilize different frequencies within those sectors) which mitigatemutual interference with respect to the adjacent cells. For example, theadjacent cell edges of cells 621 and 622 provide orthogonal frequencyface 651 due to the omni-sector of cell 621 (providing one of theadjacent cell edges) having frequency 2 assigned thereto and theomni-sector of cell 622 (providing the other of the adjacent cell edges)having frequency 1 assigned thereto. Similarly, the adjacent cell edgesof cells 621 and 625 provide orthogonal frequency face 652 due to theomni-sector of cell 621 (providing one of the adjacent cell edges)having frequency 2 assigned thereto and the omni-sector of cell 625(providing the other of the adjacent cell edges) having frequency 1assigned thereto. Accordingly, although the opposing omni-sectors ofthese cells present broadside views with respect to each other (i.e.,the azimuthal direction of the sectors, here omni-directional, are aimeddirectly at each other), their assignment of orthogonal wirelesscommunication frequencies mitigates their mutual interference.

As with the square cell deployment geometry of wireless backhaul network600 shown in FIG. 6A, the tier offset cell deployment geometry ofwireless backhaul network 700 shown in FIG. 7A provides orthogonalfrequency faces which mitigate mutual interference with respect toadjacent cells. For example, the adjacent cell edges of cells 721 and722 provide orthogonal frequency face 751 due to the omni-sector of cell721 (providing one of the adjacent cell edges) having frequency 2assigned thereto and the omni-sector of cell 722 (providing the other ofthe adjacent cell edges) having frequency 1 assigned thereto. Similarly,the adjacent cell edges of cells 721 and 725 provide orthogonalfrequency face 752 due to the omni-sector of cell 721 (providing one ofthe adjacent cell edges) having frequency 2 assigned thereto and theomni-sector of cell 725 (providing the other of the adjacent cell edges)having frequency 1 assigned thereto.

However, in the tier offset cell deployment geometry of wirelessbackhaul network 700, opposing faces are present which do not haveorthogonal frequencies associated therewith, and thus do not present anorthogonal frequency face. For example, the adjacent cell edges of cells721 and 726 provide non-orthogonal frequency face 753 due to theomni-sector of cell 721 (providing one of the adjacent cell edges)having frequency 2 assigned thereto and the omni-sector of cell 726(providing the other of the adjacent cell edges) also having frequency 2assigned thereto. However, the tier offset configuration of these cellsdisposes their hubs apart from each other a distance greater than theircell radius, thereby mitigating at least to some extent their mutualinterference. Moreover, as preferred embodiments herein implement remotenodes within the cells which use highly directional antennas, the remotenodes of such cells with opposing faces which do not have orthogonalfrequencies associated therewith will not substantially interfere withthe adjacent cell due to their being directed away from the adjacentcell. Accordingly, despite the presence of opposing faces which do nothave orthogonal frequencies associated therewith, the tier offset celldeployment geometry provides satisfactory wireless communicationoperation in various instances and provides a cell geometry option thatmay be desirable in particular situations (e.g., where cell sitelocations for square cell or other deployment configurations are notavailable). Moreover, such a tier offset cell deployment geometry mayfacilitate particular wireless backhaul expansion growth paths (e.g.,sector division and frequency assignments) which are desired over othercell geometries, such as the aforementioned square cell deploymentgeometry.

The omni-sector configurations of FIGS. 6A and 7A provide wirelesscommunication coverage of the composite service areas of the respectivewireless backhaul networks. However, as demand, usage patterns, and/orother conditions change, adequate wireless communication service may notbe provided to the remote nodes disposed within the cells of thewireless backhaul networks. For example, a multiple access technique(e.g., time division multiple access (TDMA), code division multipleaccess (CDMA), orthogonal frequency division multiple access (OFDMA),etc.) implemented within the sectors may become overloaded, and thusfail to provide a desired quality of service, when a number of remotenodes within a particular sector increases beyond some threshold number.Accordingly, although initially deploying cells with an omni-sectorconfiguration may provide a cost and/or resource effective deploymentfor providing wireless communication coverage of the wireless backhaulnetwork service area, a need for expansion in the wireless backhaulnetwork may be presented during the operational life of the network.Likewise, although cells having any number of sectors may initiallyprovide satisfactory service, a need for expansion in the wirelessbackhaul network may be presented during the operational life of thatparticular configuration.

It should be appreciated that the need for expansion may not behomogeneous within the wireless backhaul network. For example, increaseddemand may be experienced within some portion of the wireless backhaulnetwork (e.g., a more urban area) while demand remains flat within someother portion of the wireless backhaul network (e.g., a more ruralarea). Accordingly, frequency reuse patterns of embodiments herein areadapted to facilitate heterogeneous expansion in wireless backhaulnetworks (i.e., expansion in only a portion of the wireless backhaulnetwork). In particular, the frequency reuse pattern of embodiments isadapted to accommodate heterogeneous expansion in the wireless backhaulnetwork by dividing each cell of a selected cluster of cells to provideadded sectors. Frequency assignments are made according to embodimentssuch that adjacent cells provide orthogonal frequency faces with respectto one another. Such orthogonal frequency faces comprise a cell edge ofa cell associated with a frequency of the plurality of wirelesscommunication frequencies which is adjacent to a cell edge of anothercell associated with a different frequency of the plurality of wirelesscommunication frequencies to thereby mitigate mutual interference. Thefrequency assignments are further made according to embodiments suchthat, where orthogonal frequency faces are not maintained betweenadjacent cell edges as sectors are added, non-broadside common frequencyviews are provided with respect to the particular opposing sectors forwhich orthogonal frequency faces are not provided. Such non-broadsidecommon frequency views comprise the azimuthal direction of the opposingsectors being offset, such as by 20° or more, to thereby mitigate mutualinterference. Accordingly, the foregoing frequency reuse patterns areadapted to accommodate heterogeneous expansion in the wireless backhaulnetwork by dividing each cell of a selected cluster of cells to provideadded sectors while mitigating interference by maintaining theorthogonal frequency face relationships and/or providing non-broadsidecommon frequency views between opposing sectors of the wireless backhaulnetwork.

FIGS. 6B and 7B illustrate heterogeneous expansion in the wirelessbackhaul networks of FIGS. 6A and 7A, respectively, using frequencyreuse patterns in accordance with the concepts of the present invention.In the embodiments illustrated in FIGS. 6B and 7B, a cluster of cellswithin the respective wireless backhaul network is selected forexpansion by dividing each cell of a selected cluster of cells toprovide added sectors. In particular, cells 626, 627, 630, and 631 wereselected as a cluster of cells (shown as cluster 600B) for expansion inFIG. 6B. Similarly, in FIG. 7B cells 726, 727, 730, and 731 wereselected as a cluster of cells (shown as cluster 700B) for expansion. Inthe embodiments of FIGS. 6B and 7B, the cluster cells (cells 626, 627,630, and 631 of cluster 600B in FIG. 6B and cells 726, 727, 730, and 731of cluster 700B in FIG. 7B) are expanded (as compared to their previousconfiguration shown in FIGS. 6A and 7A) by dividing each cell of aselected cluster of cells to provide added sectors (shown here asomni-sectored to bi-sectored expansion).

As can be seen in FIGS. 6B and 7B, the cells external to the selectedcluster of cells selected for expansion (i.e., cells 621-624, 625, 628,629, and 632-636 in FIG. 6B and cells 721-724, 725, 728, 729, and732-736 in FIG. 7B) remain unexpanded. Thus, the expansion of thecluster cells within these exemplary wireless backhaul networks isheterogeneous.

Selection of the particular cells within a wireless backhaul network forexpansion using heterogeneous wireless backhaul network expansiontechniques of the present invention is preferably based upon a pluralityof criteria. In accordance with embodiments of the invention, at leastone cell of the cluster of cells is selected based upon a wirelessbackhaul network operational goal and at least one cell of the clusterof cells is selected based upon a heterogeneous expansion goal. Forexample, a wireless backhaul network operational goal may be to provideadditional wireless communication capacity (e.g., to serve an increasein demand) within one or more selected cell of the wireless backhaulnetwork through expanding the number of sectors and frequencyassignments in the selected cell or cells. Correspondingly, aheterogeneous expansion goal may be to expand the number of sectors andfrequency assignments of one or more cells adjacent to a cell or cellsselected for service goal expansion in order to provide orthogonalfrequency faces and/or non-broadside common frequency views with respectto the cluster cells and external cells after expansion. Accordingly,the configuration of cells comprising clusters 600B and 700B areselected according to embodiments based upon both network operationalgoals and heterogeneous expansion goals.

It should be appreciated that, although the embodiments of FIGS. 6B and7B show clusters 600B and 700B comprising 4 cells, the concepts of theinvention are not limited to clusters of 4 cells. For example, inwireless backhaul network 700, cell 726 may be selected for service goalexpansion and cell 727 may be selected for expansion goal expansion (aswill be better understood from the discussion which follows) to therebydefine a cluster of cells for heterogeneous expansion wherein suitableinterference mitigation is provided by maintaining the orthogonalfrequency face relationships and/or providing non-broadside commonfrequency views between opposing sectors of the wireless backhaulnetwork. The 4 cell cluster illustrated in FIG. 7B may, for example, bea result of cells 726 and 730 being selected for service goal expansionand cells 727 and 731 correspondingly being for expansion goalexpansion. In contrast, due to the cell deployment geometry implementedin wireless backhaul network 600, cell 626 may be selected for servicegoal expansion and cells 627, 630, and 631 may be selected for expansiongoal expansion to thereby define a cluster of cells for heterogeneousexpansion wherein suitable interference mitigation is provided bymaintaining the orthogonal frequency face relationships and/or providingnon-broadside common frequency views between opposing sectors of thewireless backhaul network. From the foregoing it should be appreciatedthat various cluster configurations (i.e., the number cluster cells, therelative positions of the cluster cells, etc.) may be utilized accordingto embodiments of the invention, such as based upon cell deploymentgeometry, sector dividing techniques used, service goals, etc.

The cluster cells of FIGS. 6B and 7B, having been expanded tomulti-sectored cells, are assigned wireless communication frequenciesimplementing an alternating frequency reuse pattern, where the twofrequency bands or channels (e.g., channels 1 and 2) are reused withineach such cell. For example, in wireless backhaul network 600, cell 626is divided diagonally to provide a bi-sectored cell configuration forthe aforementioned service goal expansion. Correspondingly, cells 627,630, and 631 are divided diagonally to provide bi-sectored cellconfigurations for the aforementioned expansion goal expansion. Thefrequency assignments for the sectors of the expanded cells are made tomaintain the orthogonal frequency faces around the periphery of cluster600B. That is, the frequency assignments made in the embodimentillustrated in FIG. 6B maintain all orthogonal frequency faces with theexternal cells (i.e., cells 622, 623, 625, 628, 629, 632, 634, and 635)that were present prior to the dividing of the cluster cells intobi-sectored cells. Accordingly, the frequency reuse plan implementedwith respect to the heterogeneous expansion in wireless backhaul network600 of FIG. 6B mitigates interference by maintaining the orthogonalfrequency face relationships between the cluster cells and the adjacentexternal cells.

In wireless backhaul network 700, cells 726 and 730 are dividedperpendicular (divided vertically in the illustrated embodiment) to theto the row offset (horizontal offset in the illustrated embodiment) toprovide a bi-sectored cell configuration for the aforementioned servicegoal expansion. Correspondingly, cells 727 and 731 are dividedperpendicular to the row offset to provide the aforementioned expansiongoal expansion. The frequency assignments for the sectors of theexpanded cells are made to maintain the orthogonal frequency facerelationships and/or provide non-broadside common frequency viewsbetween opposing sectors in wireless backhaul network 700. That is, thefrequency assignments made with respect to the left most sectors ofcells 726 and 730 and the right most sectors of cells 727 and 731maintain the orthogonal frequency faces with adjacent external cells725, 728, 729, and 732. Additionally, the frequency assignments madewith respect to the right most sectors of cells 726 and 730 and the leftmost sectors of cells 727 and 731 provide both orthogonal frequencyfaces with respect to adjacent cluster cells and non-broadside commonfrequency views (i.e., the azimuthal direction of opposing sectorshaving the same frequency assignment are offset, as represented bysector beam directional vectors 751 and 752 not pointing directly at thehub of adjacent cells 722 and 735 using a common frequency) with respectto adjacent external cells 722 and 735. Accordingly, the frequency reuseplan implemented with respect to the heterogeneous expansion in wirelessbackhaul network 700 of FIG. 7B mitigates interference by maintainingthe orthogonal frequency face relationships and by providingnon-broadside common frequency views between opposing sectors in thewireless backhaul network.

It should be appreciated from the foregoing that the dividing of thecluster cells may be performed in various configurations for maintainingthe orthogonal frequency face relationships and/or providingnon-broadside common frequency views between opposing sectors in thewireless backhaul network. For example, a particular sector divisionconfiguration used to provide heterogeneous wireless backhaul networkexpansion according to embodiments herein may be selected depending uponcell deployment geometry, the number of existing sectors and the numberof added sectors, the configurations of adjacent cell sectors, etc.Different sector division configurations (e.g., vertical, horizontal,diagonal, slant, etc.) may be utilized in various combinations within acell, as illustrated by the exemplary embodiments discussed below.

Although the foregoing heterogeneous wireless backhaul network expansionexamples illustrate frequency reuse patterns according to embodimentsherein applied with respect to expansion from omni-sector cells tobi-sector cells, the concepts of the present invention are not limitedto such sector configurations. For example, FIG. 7C shows heterogeneousexpansion from bi-sector cells to quad-sector cells and FIG. 6C showsheterogeneous expansion from quad-sector cells to octo-sector cells, allusing heterogeneous wireless backhaul network expansion techniques asdescribed above.

As with the embodiments discussed above, the frequency assignments forthe sectors of the expanded cells in the bi-sector to quad-sectorheterogeneous expansion of FIG. 7C are made to maintain the orthogonalfrequency face relationships and/or provide non-broadside commonfrequency views between opposing sectors in wireless backhaul network700. For example, the frequency assignments made with respect to theupper left most sector of cell 726 and the lower left most sector ofcell 726 maintain the orthogonal frequency faces with adjacent externalcells 721 and 725, respectively. Additionally, the frequency assignmentsmade with respect to the upper left most sector of cell 772 and thelower left most sector of cell 726 provide non-broadside commonfrequency views (i.e., the azimuthal direction of opposing sectorshaving the same frequency assignment are offset, as represented bysector beam directional vectors 761 and 762 as well as 763 and 764 notpointing directly at one another) with respect to adjacent externalcells 725 and 729, respectively. Accordingly, the frequency reuse planimplemented with respect to the heterogeneous expansion in wirelessbackhaul network 700 of FIG. 7C mitigates interference by maintainingthe orthogonal frequency face relationships and by providingnon-broadside common frequency views between opposing sectors in thewireless backhaul network according to the concepts herein.

Similarly, the frequency assignments for the sectors of the expandedcells in the quad-sector to octo-sector heterogeneous expansion of FIG.6C are made to maintain the orthogonal frequency face relationshipsand/or provide non-broadside common frequency views between opposingsectors in wireless backhaul network 600. For example, the frequencyassignments made with respect to the lower left most sector of cell 626in which frequency 2 is assigned maintains the orthogonal frequency facewith adjacent external cell 625. Additionally, the frequency assignmentsmade with respect to the upper left most sector of cell 626 in whichfrequency 1 is assigned provides non-broadside common frequency views(i.e., the azimuthal direction of opposing sectors having the samefrequency assignment are offset, as represented by sector beamdirectional vectors 661 and 662 not pointing directly at one another)with respect to adjacent external cell 625. Accordingly, the frequencyreuse plan implemented with respect to the heterogeneous expansion inwireless backhaul network 600 of FIG. 6C mitigates interference bymaintaining the orthogonal frequency face relationships and by providingnon-broadside common frequency views between opposing sectors in thewireless backhaul network according to the concepts herein.

It should be appreciated that the frequency assignments made inimplementing heterogeneous wireless backhaul network expansiontechniques according to embodiments may utilize various frequency reusepatterns to implement alternating frequency assignments as describedherein. For example, alternating frequency reuse patterns, such as theaforementioned technique wherein a second tier includes a second cellconfigured to support a second alternating reuse pattern wherein thesecond alternating frequency reuse pattern includes a first alternatingfrequency reuse pattern rotated by ninety degrees, may be utilized whenimplementing heterogeneous wireless backhaul network expansiontechniques according to embodiments of the invention.

Although the foregoing exemplary embodiments described with respect toimplementation of heterogeneous wireless backhaul network expansiontechniques are illustrated in a heterogeneous state, these wirelessbackhaul networks may nevertheless use the heterogeneous wirelessbackhaul network expansion techniques to build out homogeneous networksas well as heterogeneous networks. Examples of homogeneous networks asmay be built out using the foregoing heterogeneous wireless backhaulnetwork expansion techniques are shown in FIGS. 8A-9C. Specifically,FIG. 8A (square cell deployment geometry) and 9A (tier offset celldeployment geometry) show wireless backhaul networks homogeneously builtout to include bi-sector cells, FIGS. 8B and 9B show wireless backhaulnetworks homogeneously built out to include quad-sector cells, and FIGS.8C and 9C show wireless backhaul networks homogeneously built out toinclude octo-sector cells. It should be appreciated that the frequencyassignments implemented in the wireless backhaul network of FIG. 9Cutilizes various frequency reuse patterns to implement the alternatingfrequency assignments. In particular, the aforementioned techniquewherein the second tier includes a second cell configured to support asecond alternating reuse pattern wherein the second alternatingfrequency reuse pattern includes the first alternating frequency reusepattern rotated by ninety degrees is implemented.

It should be appreciated that wireless backhaul networks implementingconcepts of the present invention are not limited to the networkconfigurations illustrated in the exemplary embodiments. For example,wireless backhaul networks in accordance with embodiments herein maycomprise any number of cells deployed within any size and shape ofgeographic region, and thus are not limited to the relatively small,square configurations illustrated herein. Moreover, hubs (or sectorhubs) of one or more cells of any cell deployment geometry need not bedeployed where no remote node is present, thereby leaving one or morewireless communication gaps within the service area of the wirelessbackhaul network. Likewise, cell deployment geometries other than thoseof the foregoing exemplary embodiments may implement heterogeneouswireless backhaul network expansion techniques of the present invention.For example, a tier offset cell deployment geometry may implement anoffset with respect to cells of different columns rather than the rowoffset configuration illustrated in FIG. 7A. Moreover, cell deploymentgeometries may be combined, such as to dispose some cells of a firstcell deployment geometry within a wireless backhaul network having cellsof a second cell deployment geometry, to thereby provide a heterogeneouscell deployment geometry. Wireless backhaul network 1000 of FIG. 10, forexample, shows a tier offset cell deployment geometry of cells (cells1027-1033) disposed within cells of a square cell deployment geometry ofcells (cells 1021-1026 and 1031-1036), wherein cells 1027 and 1030provide a reduced cell footprint to accommodate the tier offset celldeployment geometry being disposed within the square cell deploymentgeometry.

Although embodiments have been described herein with reference to thealternating assignment of frequencies 1 and 2, it should be appreciatedthat the actual wireless communication channels need not be similarlyconfigured with respect to another instance of that frequency or anyinstance of the other frequency. For example, frequency 1 as utilized byvarious sectors of a wireless backhaul network may comprise wirelesscommunication channels of different bandwidths (e.g., 5 MHz, 7 MHz, 10MHz, etc.) as appropriate to the demand within the particular sector.Moreover, wireless communication channels designated as a particularfrequency reference (e.g., frequency 1 and frequency 2) in embodimentsherein need not actually utilize a same frequency band as anotherwireless communication channel designated as that frequency reference.That is, communication channels of different sectors designated asfrequency 1 according to embodiments herein may each comprise adifferent frequency band, as long as those frequency bands arenon-overlapping with respect to the frequency bands utilized by sectorsdesignated as frequency 2. Moreover, the sectors of embodiments hereinare not limited to the use of a single wireless communication channel.For example, a second frequency reuse pattern herein may be overlaid, orpartially overlaid, over a first frequency reuse pattern for assigningadditional wireless communication frequencies to sectors in a manneradapted to accommodate expansion in the wireless backhaul network.

A system and method for frequency reuse in a multi-cell deployment modelof wireless backhaul network, is thus described. While the invention hasbeen illustrated and described by means of specific embodiments, it isto be understood that numerous changes and modifications may be madetherein without departing from the spirit and scope of the invention asdefined in the appended claims and equivalents thereof. Furthermore,while the present invention has been described in particularembodiments, it should be appreciated that the present invention shouldnot be construed as limited by such embodiments, but rather construedaccording to the below claims.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

The one or more present inventions, in various embodiments, includecomponents, methods, processes, systems and/or apparatus substantiallyas depicted and described herein, including various embodiments,subcombinations, and subsets thereof. Those of skill in the art willunderstand how to make and use the present invention after understandingthe present disclosure.

The present invention, in various embodiments, includes providingdevices and processes in the absence of items not depicted and/ordescribed herein or in various embodiments hereof, including in theabsence of such items as may have been used in previous devices orprocesses (e.g., for improving performance, achieving ease and/orreducing cost of implementation).

The foregoing discussion of the invention has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the invention to the form or forms disclosed herein. In theforegoing Detailed Description for example, various features of theinvention are grouped together in one or more embodiments for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimed inventionrequires more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the followingclaims are hereby incorporated into this Detailed Description, with eachclaim standing on its own as a separate preferred embodiment of theinvention.

Moreover, though the description of the invention has includeddescription of one or more embodiments and certain variations andmodifications, other variations and modifications are within the scopeof the invention (e.g., as may be within the skill and knowledge ofthose in the art, after understanding the present disclosure). It isintended to obtain rights which include alternative embodiments to theextent permitted, including alternate, interchangeable and/or equivalentstructures, functions, ranges or steps to those claimed, whether or notsuch alternate, interchangeable and/or equivalent structures, functions,ranges or steps are disclosed herein, and without intending to publiclydedicate any patentable subject matter.

What is claimed is:
 1. A method for facilitating heterogeneous expansionof a wireless backhaul network including a plurality of cells providingwireless backhaul communication implementing a first wireless frequencyreuse pattern providing a first alternating utilization of a pluralityof wireless communication frequencies by the cells of the backhaulnetwork, the method comprising: identifying, by a device associated withthe wireless backhaul network, a cell cluster including a plurality ofbackhaul network cells (cluster cells) for heterogeneous expansionwithin the wireless backhaul network, wherein each cluster cell providesan orthogonal frequency face to a cell of the wireless backhaul networkexternal to the cell cluster (external cell); dividing, by the device,each cluster cell into a plurality of sectors greater than a number ofsectors provided in each cluster cell prior to the dividing; andassigning, by the device, frequencies of the plurality of wirelesscommunication frequencies to sectors of the cluster cells added by thedividing according to a second wireless frequency reuse pattern, whereinthe second wireless frequency reuse pattern provides a secondalternating utilization of the plurality of wireless communicationfrequencies within each cluster cell, wherein, after the dividing, thesectors of the cluster cells added by the dividing having a cell edgeadjacent to an external cell provide an orthogonal frequency facerelationship with the adjacent external cell or are provided anon-broadside common frequency view with respect to the external cell bythe frequency assignments, wherein cells of the wireless backhaulnetwork external to the cell cluster continue to provide wirelessbackhaul communication implementing the first wireless frequency reusepattern that provides the first alternating utilization of the pluralityof wireless communication frequencies, and wherein the first alternatingutilization of the plurality of wireless communication frequencies andthe second alternating utilization of the plurality of wirelesscommunication frequencies are different.
 2. The method of claim 1,wherein the orthogonal frequency face relationship between a portion ofeach cluster cell remaining after the dividing and an adjacent one ofthe external cells is maintained after the dividing.
 3. The method ofclaim 1, wherein the orthogonal frequency faces comprise a cell edge ofa cell associated with a frequency of the plurality of wirelesscommunication frequencies which is adjacent to a cell edge of anothercell associated with a different frequency of the plurality of wirelesscommunication frequencies.
 4. The method of claim 1, wherein theidentifying the cell cluster comprises: identifying, among the pluralityof cells included in the wireless backhaul network, at least one cellfor service goal expansion; and identifying, among the plurality ofcells included in the wireless backhaul network, one or more cellsadjacent to the at least one service goal expansion cell for expansiongoal expansion.
 5. The method of claim 4, wherein the service goalexpansion comprises expansion of the cell for meeting a wirelessbackhaul network operational goal, and wherein the expansion goalexpansion comprises expansion of the cell for meeting a heterogeneousexpansion goal.
 6. The method of claim 5, wherein the wireless backhaulnetwork operational goal comprises added bandwidth for serving increaseddemand within the at least one service goal expansion cell, and whereinthe heterogeneous expansion goal comprises facilitating providing thesectors of the cluster cells added by the dividing having a cell edgeadjacent to an external cell with an orthogonal frequency facerelationship with the adjacent external cell or a non-broadside commonfrequency view with respect to the external cell by the frequencyassignments.
 7. The method of claim 4, wherein the wireless backhaulnetwork comprises a square cell deployment geometry configuration, andwherein the cell cluster comprises 4 cells within the square celldeployment geometry having a first cluster cell and a third cluster cellutilizing a first frequency of the plurality of wireless communicationfrequencies and a second cluster cell and a fourth cluster cellutilizing a second frequency of the plurality of wireless communicationfrequencies, and wherein the first and third cluster cells are disposedin the square configuration diagonally with respect to each other andthe second and fourth cluster cells are disposed in the squareconfiguration diagonally with respect to each other.
 8. The method ofclaim 7, wherein the dividing each cluster cell into a plurality ofsectors comprises: dividing each of the cluster cells diagonally.
 9. Themethod of claim 4, wherein the wireless backhaul network comprises atier offset cell deployment geometry configuration, and wherein a cellcluster comprises 2 cells within the tier offset cell deploymentgeometry having a first cluster cell and a second cluster cell in afirst row, wherein the first row is offset with respect to an adjacentrow of cells within the tier offset cell deployment geometry, andwherein the first cluster cell utilizes a first frequency of theplurality of wireless communication frequencies and the second clustercell utilizes a second frequency of the plurality of wirelesscommunication frequencies.
 10. The method of claim 9, wherein the cellsof the wireless backhaul network provide square cellular coveragepatterns, and wherein the offset of the cells of the first row is anoffset of one half a length of a cell edge of the square cellularcoverage patterns.
 11. The method of claim 9, wherein the dividing eachcluster cell into a plurality of sectors comprises: dividing the clustercells along a line perpendicular to the row offset.
 12. A method forfacilitating heterogeneous expansion of a wireless backhaul networkincluding a plurality of cells providing wireless backhaul communicationimplementing a first wireless frequency reuse pattern providing a firstalternating utilization of a plurality of wireless communicationfrequencies by the cells of the backhaul network, the method comprising:identifying by a device associated with the wireless backhaul network, acell cluster including a plurality of backhaul network cells (clustercells) for heterogeneous expansion, wherein the cluster cells areidentified by: identifying, among the plurality of cells included in thewireless backhaul network, at least one cell for service goal expansion;and identifying, among the plurality of cells included in the wirelessbackhaul network, one or more cells adjacent to the at least one servicegoal expansion cell for expansion goal expansion; dividing each clustercell into a plurality of sectors greater than a number of sectorsprovided in each cluster cell prior to the dividing; and assigningfrequencies of the plurality of wireless communication frequencies tosectors of the cluster cells added by the dividing according to a secondwireless frequency reuse pattern, wherein the second wireless frequencyreuse pattern provides a second alternating utilization of the pluralityof wireless communication frequencies within each cluster cell, wherein,after the dividing, the sectors of the cluster cells that have a celledge adjacent to an external cell provide an orthogonal frequency facerelationship with the adjacent external cell or provide a non-broadsidecommon frequency view with respect to the external cell by the frequencyassignments, wherein cells of the backhaul network external to the cellcluster continue to provide wireless backhaul communication implementingthe first wireless frequency reuse pattern that provides the firstalternating utilization of the plurality of wireless communicationfrequencies, and wherein the first alternating utilization of theplurality of wireless communication frequencies and the secondalternating utilization of the plurality of wireless communicationfrequencies are different.
 13. The method of claim 12, wherein theservice goal expansion comprises expansion of the cell for meeting awireless backhaul network operational goal, and wherein the expansiongoal expansion comprises expansion of the cell for meeting aheterogeneous expansion goal.
 14. The method of claim 13, wherein thewireless backhaul network operational goal comprises added bandwidth forserving increased demand within the at least one service goal expansioncell, and wherein the heterogeneous expansion goal comprisesfacilitating providing the sectors of the cluster cells added by thedividing having a cell edge adjacent to an external cell with anorthogonal frequency face relationship with the adjacent external cellor a non-broadside common frequency view with respect to the externalcell by the frequency assignments.
 15. The method of claim 12, whereinthe wireless backhaul network comprises a square cell deploymentgeometry configuration, and wherein the cell cluster comprises 4 cellswithin the square cell deployment geometry.
 16. The method of claim 12,wherein the wireless backhaul network comprises a tier offset celldeployment geometry configuration, and wherein a cell cluster comprises2 cells within the tier offset cell deployment geometry.
 17. The methodof claim 16, wherein the cells of the wireless backhaul network providesquare cellular coverage patterns, and wherein the offset is an offsetof one half a length of a cell edge of the square cellular coveragepatterns.
 18. The method of claim 12, wherein an orthogonal frequencyface relationship between a portion of each cluster cell remaining afterthe dividing and an adjacent external cell is maintained after thedividing.
 19. The method of claim 12, wherein each cluster cell providesan orthogonal frequency face to a plurality of adjacent external cells,and wherein the orthogonal frequency face relationship between eachcluster cell and corresponding plurality of external cells is maintainedafter the dividing.
 20. The method of claim 12, wherein the plurality ofsectors the cluster cells are divided into comprises at least twice thenumber of sectors provided in each cluster cell prior to the dividing.21. A wireless backhaul network, comprising: a plurality of cellssupporting wireless backhaul communication within a corresponding cellfootprint portion of the wireless backhaul network; a cluster of cellswithin the plurality of cells that has been divided into a number ofsectors greater than a number of sectors of adjacent cells of thewireless backhaul network external to the cluster to thereby provide aheterogeneous cell configuration within the wireless backhaul network;and a frequency reuse plan providing alternating assignments of aplurality of frequencies to the plurality of cells so as to facilitatethe heterogeneous cell configuration by providing a first alternatingassignment of the plurality of frequencies with respect to the sectorsof the cluster cells to provide all cell edges adjacent to an externalcell with either an orthogonal frequency face relationship with theadjacent external cell or a non-broadside common frequency view withrespect to the adjacent external cell and by providing a secondalternating assignment of the plurality of frequencies with respect tothe external cells to provide cell edges between adjacent external cellswith an orthogonal frequency face relationship or a non-broadside commonfrequency view.
 22. The wireless backhaul network of claim 21, whereinthe plurality of cells are disposed in a square cell deploymentgeometry.
 23. The wireless backhaul network of claim 21, wherein theplurality of cells are disposed in a tier offset cell deploymentgeometry.
 24. The wireless backhaul network of claim 23, wherein thecells supporting wireless backhaul communication provide square cellularcoverage patterns, and wherein the offset is an offset of one half alength of a cell edge of the square cellular coverage patterns.
 25. Thewireless backhaul network of claim 21, wherein the number of sectors ofthe cluster cells is at least twice the number of sectors of theadjacent cells external to the cluster.
 26. The wireless backhaulnetwork of claim 25, wherein the number of sectors of the cluster cellsis 2 and the number of sectors of the adjacent cells external to thecluster is
 1. 27. The wireless backhaul network of claim 25, wherein thenumber of sectors of the cluster cells is 4 and the number of sectors ofthe adjacent cells external to the cluster is
 2. 28. The wirelessbackhaul network of claim 25, wherein the number of sectors of thecluster cells is 8 and the number of sectors of the adjacent cellsexternal to the cluster is 4.